Drug Interactions between Iron Sulfate and nicotinamide

ADJUST DOSING INTERVAL: Concomitant use of some oral medications may reduce the bioavailability of orally administered iron, and vice versa.

Food taken in conjunction with oral iron supplements may reduce the bioavailability of the iron. However, in many patients intolerable gastrointestinal side effects occur necessitating administration with food.

MANAGEMENT: Ideally, iron products should be taken on an empty stomach (i.e., at least 1 hour before or 2 hours after meals), but if this is not possible, administer with meals and monitor the patient more closely for a subtherapeutic effect. Some studies suggest administration of iron with ascorbic acid may enhance bioavailability. In addition, administration of oral iron products and some oral medications should be separated whenever the bioavailability of either agent may be decreased. Consult the product labeling for specific separation times and monitor clinical responses as appropriate.

GENERALLY AVOID: Ethanol can exacerbate the cutaneous flushing that is a common side effect of niacin. At least one case of delirium and lactic acidosis has been reported with coadministration of these drugs, although data are limited.

MANAGEMENT: Coadministration should probably be discouraged, particularly since chronic consumption of large amounts of alcohol is associated with hyperlipidemia.

A single case has been reported in which cutaneous flushing and tremors were noted in a woman who was taking niacin while wearing a nicotine patch. The mechanism is suspected to be synergistic cutaneous vasodilatory effects. The clinical significance of this possible interaction is not known.